2005-04-16 16:20:36 -06:00
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/*
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2007-09-20 02:31:38 -06:00
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* fs/sysfs/symlink.c - sysfs symlink implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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2005-04-16 16:20:36 -06:00
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*/
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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2007-07-26 08:53:53 -06:00
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#include <linux/mutex.h>
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2009-09-09 12:25:37 -06:00
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#include <linux/security.h>
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2005-04-16 16:20:36 -06:00
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#include "sysfs.h"
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2013-01-25 13:51:13 -07:00
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static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
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struct kobject *target,
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const char *name, int warn)
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2005-04-16 16:20:36 -06:00
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{
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2013-11-23 15:21:50 -07:00
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struct sysfs_dirent *sd, *target_sd = NULL;
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2005-04-16 16:20:36 -06:00
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2013-01-25 13:51:13 -07:00
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BUG_ON(!name || !parent_sd);
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2007-06-13 12:45:15 -06:00
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2013-10-30 08:28:36 -06:00
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/*
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* We don't own @target and it may be removed at any time.
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* Synchronize using sysfs_symlink_target_lock. See
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* sysfs_remove_dir() for details.
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2007-06-13 12:45:15 -06:00
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*/
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2013-10-30 08:28:36 -06:00
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spin_lock(&sysfs_symlink_target_lock);
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2013-11-28 12:54:30 -07:00
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if (target->sd) {
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target_sd = target->sd;
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kernfs_get(target_sd);
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}
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2013-10-30 08:28:36 -06:00
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spin_unlock(&sysfs_symlink_target_lock);
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2007-06-13 12:45:15 -06:00
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if (!target_sd)
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2013-11-23 15:21:50 -07:00
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return -ENOENT;
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2007-07-18 01:14:45 -06:00
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2013-11-23 15:21:50 -07:00
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sd = kernfs_create_link(parent_sd, name, target_sd);
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2013-11-28 12:54:30 -07:00
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kernfs_put(target_sd);
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2007-07-18 01:38:11 -06:00
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2013-11-23 15:21:50 -07:00
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if (!IS_ERR(sd))
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return 0;
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2007-06-13 13:27:24 -06:00
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2013-11-23 15:21:50 -07:00
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if (warn && PTR_ERR(sd) == -EEXIST)
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sysfs_warn_dup(parent_sd, name);
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return PTR_ERR(sd);
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2005-04-16 16:20:36 -06:00
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}
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2013-01-25 13:51:13 -07:00
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/**
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* sysfs_create_link_sd - create symlink to a given object.
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* @sd: directory we're creating the link in.
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* @target: object we're pointing to.
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* @name: name of the symlink.
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*/
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int sysfs_create_link_sd(struct sysfs_dirent *sd, struct kobject *target,
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const char *name)
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{
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return sysfs_do_create_link_sd(sd, target, name, 1);
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}
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static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
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const char *name, int warn)
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{
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struct sysfs_dirent *parent_sd = NULL;
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if (!kobj)
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2013-11-28 12:54:39 -07:00
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parent_sd = sysfs_root_sd;
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2013-01-25 13:51:13 -07:00
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else
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parent_sd = kobj->sd;
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if (!parent_sd)
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return -EFAULT;
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return sysfs_do_create_link_sd(parent_sd, target, name, warn);
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}
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2008-06-10 03:09:08 -06:00
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/**
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* sysfs_create_link - create symlink between two objects.
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* @kobj: object whose directory we're creating the link in.
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* @target: object we're pointing to.
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* @name: name of the symlink.
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*/
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int sysfs_create_link(struct kobject *kobj, struct kobject *target,
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const char *name)
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{
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return sysfs_do_create_link(kobj, target, name, 1);
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}
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2013-08-21 17:17:47 -06:00
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EXPORT_SYMBOL_GPL(sysfs_create_link);
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2008-06-10 03:09:08 -06:00
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/**
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* sysfs_create_link_nowarn - create symlink between two objects.
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* @kobj: object whose directory we're creating the link in.
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* @target: object we're pointing to.
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* @name: name of the symlink.
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*
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2012-09-04 05:23:35 -06:00
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* This function does the same as sysfs_create_link(), but it
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2008-06-10 03:09:08 -06:00
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* doesn't warn if the link already exists.
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*/
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int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
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const char *name)
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{
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return sysfs_do_create_link(kobj, target, name, 0);
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}
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2010-03-30 12:31:28 -06:00
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/**
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* sysfs_delete_link - remove symlink in object's directory.
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* @kobj: object we're acting for.
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* @targ: object we're pointing to.
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* @name: name of the symlink to remove.
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*
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* Unlike sysfs_remove_link sysfs_delete_link has enough information
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* to successfully delete symlinks in tagged directories.
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*/
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void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
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const char *name)
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{
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const void *ns = NULL;
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2013-10-30 08:28:36 -06:00
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/*
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* We don't own @target and it may be removed at any time.
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* Synchronize using sysfs_symlink_target_lock. See
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* sysfs_remove_dir() for details.
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*/
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spin_lock(&sysfs_symlink_target_lock);
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2013-11-29 15:19:09 -07:00
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if (targ->sd && kernfs_ns_enabled(kobj->sd))
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2010-03-30 12:31:28 -06:00
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ns = targ->sd->s_ns;
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2013-10-30 08:28:36 -06:00
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spin_unlock(&sysfs_symlink_target_lock);
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2013-11-23 15:21:49 -07:00
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kernfs_remove_by_name_ns(kobj->sd, name, ns);
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2010-03-30 12:31:28 -06:00
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}
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2005-04-16 16:20:36 -06:00
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/**
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* sysfs_remove_link - remove symlink in object's directory.
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* @kobj: object we're acting for.
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* @name: name of the symlink to remove.
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*/
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2013-08-21 17:28:26 -06:00
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void sysfs_remove_link(struct kobject *kobj, const char *name)
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2005-04-16 16:20:36 -06:00
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{
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2008-01-29 15:35:18 -07:00
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struct sysfs_dirent *parent_sd = NULL;
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if (!kobj)
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2013-11-28 12:54:39 -07:00
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parent_sd = sysfs_root_sd;
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2008-01-29 15:35:18 -07:00
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else
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parent_sd = kobj->sd;
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2013-11-23 15:21:49 -07:00
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kernfs_remove_by_name(parent_sd, name);
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2005-04-16 16:20:36 -06:00
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}
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2013-08-21 17:17:47 -06:00
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EXPORT_SYMBOL_GPL(sysfs_remove_link);
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2005-04-16 16:20:36 -06:00
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2010-02-12 20:22:25 -07:00
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/**
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2013-09-11 20:29:06 -06:00
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* sysfs_rename_link_ns - rename symlink in object's directory.
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2010-02-12 20:22:25 -07:00
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* @kobj: object we're acting for.
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* @targ: object we're pointing to.
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* @old: previous name of the symlink.
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* @new: new name of the symlink.
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2013-09-11 20:29:06 -06:00
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* @new_ns: new namespace of the symlink.
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2010-02-12 20:22:25 -07:00
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*
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* A helper function for the common rename symlink idiom.
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*/
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2013-09-11 20:29:06 -06:00
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int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
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const char *old, const char *new, const void *new_ns)
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2010-02-12 20:22:25 -07:00
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{
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struct sysfs_dirent *parent_sd, *sd = NULL;
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2013-09-11 20:29:06 -06:00
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const void *old_ns = NULL;
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2010-02-12 20:22:25 -07:00
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int result;
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if (!kobj)
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2013-11-28 12:54:39 -07:00
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parent_sd = sysfs_root_sd;
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2010-02-12 20:22:25 -07:00
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else
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parent_sd = kobj->sd;
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2010-03-30 12:31:26 -06:00
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if (targ->sd)
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old_ns = targ->sd->s_ns;
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2010-02-12 20:22:25 -07:00
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result = -ENOENT;
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2013-11-28 12:54:30 -07:00
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sd = kernfs_find_and_get_ns(parent_sd, old, old_ns);
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2010-02-12 20:22:25 -07:00
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if (!sd)
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goto out;
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result = -EINVAL;
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if (sysfs_type(sd) != SYSFS_KOBJ_LINK)
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goto out;
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2013-11-28 12:54:14 -07:00
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if (sd->s_symlink.target_sd->priv != targ)
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2010-02-12 20:22:25 -07:00
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goto out;
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2013-11-23 15:21:51 -07:00
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result = kernfs_rename_ns(sd, parent_sd, new, new_ns);
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2010-02-12 20:22:25 -07:00
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out:
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2013-11-28 12:54:30 -07:00
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kernfs_put(sd);
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2010-02-12 20:22:25 -07:00
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return result;
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}
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2013-09-11 20:29:06 -06:00
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EXPORT_SYMBOL_GPL(sysfs_rename_link_ns);
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